121819

Appears in sequences

• Parent nodes of nonzero terms of A262509: a(n) = A049820(A262509(n)).at n=24A262510
• Number of nX5 0..n+5-2 arrays with upper left zero and lower right n+5-2 and each element differing from its horizontal and antidiagonal neighbors by one or two.at n=2A265463
• T(n,k)=Number of nXk 0..n+k-2 arrays with upper left zero and lower right n+k-2 and each element differing from its horizontal and antidiagonal neighbors by one or two.at n=23A265466
• Number of 3Xn 0..3+n-2 arrays with upper left zero and lower right 3+n-2 and each element differing from its horizontal and antidiagonal neighbors by one or two.at n=4A265468